bacillus thuringiensis
 

Hello all
I've found a supplier who will ship a product containing bacillus thuringiensis to me here in The Canaries.
I want to try it on my citrus trees in an effort to control Citrus Leaf Miner - the little bast*rds have decimated my trees for the last 2 years.
I've tried Neem oil and other pesticides to no avail. I've even sprayed the trees with the most obnoxious aftershave I could buy cheaply - it was meant to confuse the moths - all it did was make me stink, even after a couple of showers! I can't keep up with squashing them by hand.
So, my question is, has anyone used bacillus thuringiensis and can give me some advice?
Do I just spray once and that is it for ever? Or do I need to spray each season, or every month?

Hopefully details will be on the product when it arrives - I couldn't read the pic online - but I'd like to hear of anyone's experience of using it while I'm waiting.
Thanks

It is the go-to product for all sorts of insect larvae. It doesn't touch the adults, is harmless to humans and pets. It gives the caterpillars and other wormy-things a tummy ache... they stop feeding and die. So keep it away from your milkweed... The instructions should indicate how often, it doesn't need to hit the "targets", but when it's on whatever they are feeding on - leaves, fruit, etc. it kills them. It is not systemic. Since you don't get significant rain during the growing season, you probably don't need it too frequently since it won't wash off unless you water the foliage.

Does it work against leaf miners?

Worth a try... I don't know how specific it is with respect to the larvae of various species, but basically it is the only thing that targets that destructive stage of life of insects. I got it in a hose-end sprayer (Home Depot) to anoint my avocado tree when I had a caterpillar attack and it did the job. Since it isn't toxic to people at all, approved for organic gardening, what do you have to lose other than the price of the product to try?

You can read about the effectiveness of BT against leaf miners here: [PDF] Efficacy of Bacillus thuringiensis against Phyllocnistis citrella (Lepidoptera: Phyllocnistidae). | Semantic Scholar

Don’t know if you can get them where you are, but people around here use hormone traps with good success if you replace them often enough.

Our LM pressure may be lower than yours since we usually only worry about LM damage on very young trees. Established trees typically have enough foliage that the damage done to leaves during peak LM season isn’t really an issue. If the Bt doesn’t work, spinosad would be next on my list.

Use soft water with a pH a little above 7 with both of these pesticides. Hard water and water with an acidic pH will reduce the effectiveness of both.

Thank you so much to everyone who has responded!

I got a bit overwhelmed reading some of Semantic Scholar articles but am encouraged that this might be the answer for me.

I can't get the traps here, or Spinosad.

I have 8 assorted citrus trees, all about 2 years old, and hardly an untouched leaf amongst them :(

Unless the info on the product says otherwise my plan is to give an initial spay, repeat it if we ever get any rain, repeat it when I get a flush of new growth.

I normally only spray the leaves with water when we have had a calima, to give them a freshen up - I'll think carefully before doing this in future.

My water is around 5.5pH at the moment - I have pH plus liquid that I use for the swimming pool - can I use that or is there something more natural that would be preferable?

Once again, thank you so much; you wonderful bunch of helpful and knowledgeable people :bowing

What is in the ph-plus product? If it is sodium bicarbonate or sodium-anything), sodium is undesirable. Calcium carbonate would be better as a pH raiser. Pretty insoluble at higher concentrations, but at low concentrations (especially since your water is pretty acidic) probably would do the job. Or something with potassium. I am sure one of our more "chemically savvy" members would have a better idea, again depending on what is in you pool product, may be fine.

Just had a look - it's Sodium something :(

For calcium carbonate, look for limestone or dolomite lime. At pH 5.5 some will dissolve. Worth seeing what it does. Or, you can actually get powdered calcium carbonate... several sources came up when I googled it. That's the active ingredient in many antacids... so certainly non-toxic but you'd want to use a version without the flavorings.